The present application relates to reducing crosstalk for a display.
A display suitable for displaying a color image usually consists of three color channels to display the color image. The color channels typically include a red channel, a green channel, and a blue channel (RGB) which are often used in additive displays such as a cathode ray tube (CRT) display and a liquid crystal display (LCD). In additive color displays, it is assumed that color primaries are additive and that the output color is the summation of its red, green, and blue channels. In order to achieve the optimal color output, the three color channels are independent from one another, i.e. the output of red channel should only dependent on the red value, not the green value or the blue value.
In cathode ray tub (CRT) displays, shadow masks are often used to inhibit electrons in one channel from hitting phosphors of other channels. In this manner, the electrons associated with the red channel primarily hit the red phosphors, the electrons associated with the blue channel primarily hit the blue phosphors, and the electrons associated with the green channel primarily hit the green phosphors. In a liquid crystal displays (LCD), a triad of three subpixels (or other configurations) is used to represent one color pixel as shown in FIG. 1. The three subpixels are typically identical in structure with the principal difference being the color filter.
The use of color triads in a liquid crystal display provides independent control of each color; but, sometimes, the signal of one channel can impact the output of another channel, which is generally referred to as crosstalk. Accordingly, the signals provided to the display are modified in some manner so that some of the colors are no longer independent of one another. The crosstalk may be the result of many different sources, such as for example, capacitive coupling in the driving circuit, electrical fields from the electrodes, or undesirable optical “leakage” in the color filters. While the optical “leakage” in the color filters can be reduced using a 3×3 matrix operation, the electrical (e.g., electrical fields and capacitive coupling) crosstalk is not reduced using the same 3×3 matrix operation.
Typical color correction for a display involves color calibration of the display as a whole using a calorimeter, and then modifying the color signals using a color matrix look up table (LUT). The same look up table is applied to each pixel of the display in an indiscriminate manner. The calorimeter is used to sense large uniform patches of color and the matrix look up table is based upon sensing this large uniform color patch. Unfortunately, the resulting color matrix look up table necessitates significant storage requirements and is computationally expensive to compute. It is also inaccurate since it ignores the spatial dependence of crosstalk (i.e. correcting for the color of low frequencies causes high frequency color inaccuracies).